Download - Understanding Computers - Today and Tomorrow
What is a computer?
A computer is a programmable, electronicdevice that accepts data, performs operationson that data, presents the results, and storesthe data or results as needed
What does a computer do? A computer can perform four general operations:
Input (entering data into a computer)
Processing (performing operations on the data)
Output (presenting the results)
Storage (saving data, programs, or output)
Data vs. Information
Data: almost any kind of fact or set of facts Information Processing: the conversion of data
into information Information: processed data into a meaningful form
Data
• Raw, unorganized, unprocessed facts
Information Processing
Information
• Data that has been processed into a meaningful form
What is hardware?
Hardware is thephysical part ofa computer, thatyou can touch
Examples:
Keyboard
Mouse
Monitor
Printer
Scanner
speaker
What is software?
Software refers to the programs or instructionsused to tell the computer hardware what to do
Types of software: 1. System Software The programs that
allow a computer to operate are collectively referred to as system software.
Examples:
Windows, Mac
LINUX, UNIX
Android, Symbian
Types of software: 2. Application Software Application
software consists of programs designed to allow people to perform specific task
Examples:
Microsoft Office (Word, Excel, PowerPoint, Access)
Adobe Photoshop, Acrobat
Internet explorer
Types of Users
Computer Users (End Users) -- People whouse computers to perform tasks or obtaininformation
Programmers – Computer Professionals whowrite, test, and maintain computer programs
System Analysts – Computer Professionals whoanalyze and design computer systems to solvebusiness problems
Operations Personnel – Computer Professionalswho are responsible for the day-to-day computeroperations
Types of computers: 1. Embedded Computers A tiny computer
embedded into a product and designed to perform specific tasks or functions
Examples: Washing machine
Microwave
Televisions
Cars
Types of computers: 2. Mobile Devices A very small
communication device with built-in computing or internet capability
Examples: Smart phones
Smart watches
Handheld gaming devices
Portable digital media players
Types of computers: 3. Personal Computers A computer
designed to be used by one person at a time
Examples: Desktop Computers Portable Computers
(Notebook/Laptop, Tablet, Netbook, Ultra-mobile PC/Handheld Computer)
Types of computers: 4. Midrange Server/Computer
A medium-sized computer used to host programs and data for a small network
Example:
Medical or dental offices
School computer lab
Home & small business servers
Types of computers: 5. Mainframe Computer A powerful
computer used by many large organizations to manage large amounts of centralized data and programs
Examples:
Hospitals
Universities
Banks
Government offices
Types of computers: 6. Supercomputer
The most powerful and most expensive computer for complex computations and processing
Examples:
Space Missions and Satellite Controls
Weather forecasting
Oil exploration
Scientific research
Basic types of data
Multimedia
Integration of multiple forms of media
Computer information represented through audio, video, animation, in addition to, text, image
Data
Text Number Image Audio Video
Digital data representation
Bit (Binary digit) --the smallest unit of data that can be stored in a computer (0 or 1)
Byte -- a group of 8 bits
Bit Pattern -- a string of bits, example, 10011101110110001
Data Unit Conversion1 KB (Kilobyte) ≈ 1 thousand bytes
1 MB (Megabyte) ≈ 1 million bytes
1 GB (Gigabyte) ≈ 1 billion bytes
1 TB (Terabyte) ≈ 1 trillion bytes
1 PB (Petabyte) ≈ 1000 terabytes
1 0 1 0 1 1 0 0
Byte
Bit
Coding Standards for Text-based Data (Characters) ASCII (American Standard Code for
Information Interchange)
uses 7-bit code to represent each character
Each 7-bit code can represent up to 128 characters (27 unique combinations)
Extended ASCII
uses 8-bit code to represent each character
Each 8-bit code can represent up to 256 characters (28 unique combinations)
EBCDIC (Extended Binary Coded Decimal Information Code)
uses 8-bit code to represent each character
Each 8-bit code can represent up to 256 characters (28 unique combinations)
Unicode
Universal international coding standard to represent text-based data in any language
uses (8-bit to 32-bit) code to represent each character
ISO (International Organization for Standardization)
uses 32-bit code to represent each character
Each 32-bit code can represent up to 232
characters
Types of images: 1. Bitmap Graphic made of a grid or matrix of small dots (pixels; picture
elements) The color at each pixel is represented by binary
code/number
0 00 0 0 0 0 0
0 0
0 00 0 0 0 0 0
0 11 1 1 1 1 0
0 011 1 1 1 1
11 1 1 1 1
For monochrome (Black & White) graphic image
Types of images: 2. Vector Graphic made of lines, curves and shapes based on vectors (paths) that lead through locations
(control points or nodes) all lines, curves, or shapes are represented by
mathematical formulas
AudioThe procedure to convert analog sound to digital sound1) analog signal is sampled
2) samples are quantized
3) The quantized values are coded into binary patterns
Video A collection of frames (images) that are projected in
sequence dynamically
Each image data is converted to a set of bit patterns and stored
Numerical data representation
Decimal number system – based on 10 symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) Binary number system – based 2 symbols (0, 1) Octal number system – based on 8 symbols (0, 1, 2, 3, 4, 5, 6, 7)
Each octal number is represented in binary form as 3-bit pattern
Hexadecimal number -- based on 16 symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F)
Each hexadecimal number is represented in binary form as 4-bit pattern
0 1 2 3 4 5 6 7
000 001 010 011 100 101 110 111
0 1 2 3 4 5 6 7 8 9 A B C D E F
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Conversion: Decimal to Binary
Decimal (25)10 = binary (11001)2
2512631
101 1 0
Procedure: Divide the decimal number by 2 and write down remainders successively
Conversion: Decimal to Binary
Decimal (35)10 = binary (100011)2
35178421
1101 0 0
Procedure: Divide the decimal number by 2 and write down remainders successively
Conversion: Binary to Decimal
Binary (11001)2 = Decimal (25)10
16 8 0 0 1 25
16 8 4 2 1
1 1 0 0 1
Procedure: Multiply the binary number by multiple of 2 respectively and add all
Conversion: Binary to Decimal
Binary (100011)2 = Decimal (35)10
32 0 0 0 2 1 35
32 16 8 4 2 1
1 0 0 0 1 1
Procedure: Multiply the binary number by multiple of 2 respectively and add all
Motherboard– main electronic circuit board inside system unit that contains computer chips and other connected components
Central Processing Unit (CPU)/Processor– chip located on motherboard of computer that performs processing for the computer
o Multi-core CPU– CPU that contains processing components or core of more than one processor in a single CPU
o Dual-core CPU– CPU that contains two separate processing coreso Quad-core CPU– CPU that contains four separate processing cores
Bus– electronic path on motherboard along which data is transferredExample:Memory bus, Front-side bus, PCI and PCI Express bus, USB bus, FireWire/IEEE 1394 bus
Port– the exteriorof the computer to whichA device may be attached using a connectorExample:Monitor port, Network port,Modem port, USB port, FireWire(IEEE 1394) port,Keyboard port, SCSI (Small ComputerSystem Interface) port,MIDI port, Audio port, etc.
Volatile memory (Primary Storage)Memory refers to chip-based storageRAM (Random Access Memory) – This main-memory integrated-chip of computer provides temporary location to hold data and programs. Generally, it is volatile (the memory content is erased when the computer is powered down), except nonvolatile-RAMSRAM (Static Random Access Memory) – This volatile
memory is faster but expensive. It uses electronic flip – flop gates (a gate with two states: 0 and 1) to hold data. It doesn’t need memory refreshing.
DRAM (Dynamic Random Access Memory)– This volatile memory is slower but inexpensive. It uses electronic capacitors (charged or discharged states as 1 or 0) to hold data. It needs constant memory refreshing.
Cache Memory– group of fast memory circuitry located on or near CPU to help speed up processingRegister– high-speed memory built into CPU that temporarily stores data during processing
ROM (Read Only Memory) --nonvolatile memory chip that permanently stores data or programs in general.
PROM(Programmable Read Only Memory) – nonvolatile memory chip that can be programmed/written only once (one-time).
EPROM (Erasable Programmable Read Only Memory) –nonvolatile memory chip that can be erased and reprogrammed/rewritten many times.
Non-volatile memory
Storage systemsFloppy Disk -- low-capacity, removable disk made of flexible plastic
Hard Drive – are used to store programs and data
MagneticHardDrive/Disk –contains metal hard disks that are tracked with magnetic spots representing 0s and 1s
Solid StateDrive (SSD) –uses flash memory technology to store data and programs
Hybrid Harddrive – a combination of magnetic hard drive and solid-state drive (contains flash memory together with magnetic hard disks)
Optical Disc – thin circular disc that stores and reads data using laser beam (optically) CD (Compact Disc) – low
capacity (typically 650 MB) optical disc that uses infrared laser for data storage
DVD (Digital Versatile Disc) –medium capacity (typical 4.7 GB to 8.5 GB) optical disc that uses red laser for data storage
BD (Blue-ray Disc) – high-capacity (typically 25 GB to 50 GB) disc that uses blue-violet laser for data storage
CD-ROM, DVD-ROM, and BD-ROM discsThese discs are read-only optical discs that come prerecorded and user can not writeCD-R, DVD-R, DVD+R, and BD-R discsThese discs are recordable optical discs (write-once discs) but can not be erased afterwardCD-RW, DVD-RW, DVD+RW, and BD-RE discsThese discs are rewritable optical discs that can be written to, erased, and overwritten many times
Flash Memory-- a chip-based storagemedium that stores datausing electrons (electricalcharge trapped or not, i.e., 0or 1) within flash memory cell Flash Memory Cards –
small, rectangular flashmemory medium containingchips, such as a Compact Flash(CF) or Secure Digital (SD)card
USB Flash Drive (UniversalSerial Bus Drive) -- smallstorage device that plugs intoUSB port and contains flashmemory media
Input DevicesKeyboard -- input device containing numerous keys that can be used to input letters, numbers, and other symbolsMouse -- common pointing device that user slides along a flat surface to move pointerElectronic pen -- input device that is used to write electronically on the display screenScanner -- input device that reads printed text and graphics and transfers them to a computer in digital formExamples: Flatbed Scanner, Handheld Scanner, Integrated ScannerTouch Screen– display device that is touched with finger to issue commands
Readers – input devices that read different types of codes and marks as well as individual’s biometric characteristics1. Barcode Reader-- an input device that reads barcode (optical code)
5. RFID(Radio Frequency Identification)Reader— device used to read RFID tags (tiny chip with radio antenna to be identified using RFID technology)
2. OMR(Optical Mark Readers)– an input device to input data from special forms to score or tally exams, questionnaires, ballots, etc.)
3. OCR(Optical Character Recognition) Reader– used to recognize scanned text characters (from monthly bills for credit cards or utilities companies, etc.) and convert into electronic form as text4. MICR(Magnetic Ink CharacterRecognition) Reader– used to read and add magnetic-inked MICR characters primarily during bank check/cheque processing
6. Biometric Reader— device used to input biometric data, such as fingerprint, voice, face
Output Devices Display device— an
output device that contains a viewing screen Monitor-- display
device for desktop computer
Display Screen–display device built into a notebook computer, netbook, UMPC etc.
Flat-panel display–slim type of display device that uses electronically charged chemicals or gases
Display Device Characteristics
Color vs. Monochrome Display Devices– display devices form images by lighting up the proper configurations of pixels (the dots or the smallest colorable areas on a display device); picture elements
Color Display Device-- each pixel can display a combination of three colors (red, green, and blue)
Monochrome Display Device-- Each pixel can only be one of two colors (Black or White)
CRT Monitors vs. Flat-Panel Displays
CRT Monitor Display -- uses cathode-ray tube technology (electron gun projects an electron beam at a screen coated with red, green, and blue phosphor dots)
Flat-Panel Display-- uses electronically charged chemicals or gases filled in between thin panes of glass or other transparent material
Audio Output-- includes voice, music, and other audible soundsTypes of audio output devices:-- Computer Speaker-- output device connected to computers that provide audio output-- Headphone– personal audio output device used by an individual to hear sound-- Headset– headphone with a built-in microphone
Flat-Panel Display Technologies
-- Liquid Crystal Display (LCD) – uses charged liquid crystals located between two sheets of glass or plastic-- Organic Light Emitting Diode (OLED) Display– uses emissive organic material to display brighter and sharper images-- Plasma Display– uses layered technology (a layer of gas between two plates of glass) to display images-- Data Projector– display device that projects all computer output to a wall or projection screen
Printer– output device that produces output on paperPrinter Characteristics– technology used, size, speed, print quality, etc.
Printing Technology– Printers produce images through either impact or nonimpact technologies
Impact Printer– have a print mechanism that actually strikes the paper to transfer ink to the paperExample: dot-matrix printer
Nonimpact Printer– have a print mechanism that does not strike/touch the paper to transfer ink to paperExample: Laser printer, ink-jet printer
Color vs. Black & White Printers
─ Color printer uses black, blue, red, yellow ink to print a document
─ often used in homes─ expensive and slow
speed
─ Black & White printer uses black ink to print a document
─ Mostly used in business or office places
─ Less expensive and faster speed
Personal vs. Network Printers
o Personal printer is designed to connect directly to a computer
o can not be shared
o Network printer is designed to connect directly to a home or office network
o can be shared over a network
Print Resolution (dpi)– the number of dots (of liquid ink or toner powder flecks) per inch
Print Speed (ppm)– measured in pages per minute
Laser printer– output device that uses laser beam (to charge drum locations) and toner powder to print on paperInk-jet Printer– output device that sprays droplets of ink to produce images on paperPhoto Printer– output device designed for printing digital photographsBarcode Printer– output device that print custom barcodes on price tags, shipping labels etc.Portable Printer– small lightweight printer designed to be used while on the goPlotter/Wide-Format Printer– used to print large documents, such as charts, drawings, maps, blueprints, posters, banners etc.3D Printer– output device designed to print three-dimensional objects, such as product prototypes etc.
Algorithm-- a step by step procedure for solving a
problem
Flowchart– diagram that represents steps of an algorithm, workflow or process sequentiallyExample: adding two numbers; A, B
Pseudo Code– informal description of an algorithm in plain EnglishExample: adding two numbers; X, Y
Begininput Xinput YSum = X + Yprint Sum
End
ComputerLanguages
Machine Language--binary-based language for representing computer programs that the computer can execute directly
Assembly Language–a low-level programming language in which each statement produces exactly one machine instruction
Assembler-- a program for converting Assembly language code into Machine code
High-level Language–more understandable and portable language in which each statement accomplish substantial tasks
Compiler– a program for converting High-level language code into low-level code or binary form
What is computer network?
collection of computers and other hardware devices that are connected together to share hardware, software, and data, as well as to communicate electronically with one another
Internet
Internet benefits
Web Browsing
Chatting and Entertainment
Communication & business
Information sharing
the largest computer network in the world
Types of networks: 1. Local Area Network
A network that connects devices located in a small geographical area, such as within a building
Types of networks: 3. Wide Area Network (WAN) A network that connects devices located in a large
geographical area
Operating System The main component of system software that
enables the computer to manage its activities andthe resources under its control, run applicationprograms, and interface with the user
Function/Benefits of operating system
Interfacing with Users Booting the Computer Configuring Devices Managing and Monitoring Resources and
Jobs File Management Security
Differences among Operating Systems
Graphical User Interface vs. Command Line
Graphical user interface (GUI)– graphics-based interface that allows a user to communicate instructions to the computer easily
Command line interface--user interface that requires the user to communicate instructions to the computer via typed commands